Final answer:
The correct preposition to complete the sentence is 'devant', meaning 'in front of'.
Step-by-step explanation:
The correct preposition to complete the sentence is devant. In French, devant means 'in front of'. So the complete sentence would be 'Mon chien est devant la maison', which translates to 'My dog is in front of the house'.
Learn more about Prepositions in French